A 19 year old man is fighting for his life following an assault in Swords yesterday evening.
It happened on Brookdale Avenue at around 7pm.
Gardaí are describing it as as a serious assault.
Its understood he suffered stab wounds.
The man was taken to Beaumont Hospital - where he remains - in critical condition.
A man in his early 20s has been arrested, and is being detained at Swords Garda station.
He is being held under section 4 of the Criminal Justice Act.
Gardaí are appealing for any witnesses to the attack to come forward.